If we can have illusions about our bodies, how much more can we about other people?

A recent study, The Marble Hand Illusion, demonstrates that by simple manipulation of perceptual input, people can be induced to change their perceptions of their own bodies.

The authors state that:

“This novel bodily illusion, the ‘Marble-Hand Illusion’, demonstrates that the perceived material of our body, surely the most stable attribute of our bodily self, can be quickly updated through multisensory integration.”

The full abstract says:

Our body is made of flesh and bones. We know it, and in our daily lives all the senses constantly provide converging information about this simple, factual truth. But is this always the case? Here we report a surprising bodily illusion demonstrating that humans rapidly update their assumptions about the material qualities of their body, based on their recent multisensory perceptual experience. To induce a misperception of the material properties of the hand, we repeatedly gently hit participants’ hand with a small hammer, while progressively replacing the natural sound of the hammer against the skin with the sound of a hammer hitting a piece of marble. After five minutes, the hand started feeling stiffer, heavier, harder, less sensitive, unnatural, and showed enhanced Galvanic skin response (GSR) to threatening stimuli. Notably, such a change in skin conductivity positively correlated with changes in perceived hand stiffness. Conversely, when hammer hits and impact sounds were temporally uncorrelated, participants did not spontaneously report any changes in the perceived properties of the hand, nor did they show any modulation in GSR. In two further experiments, we ruled out that mere audio-tactile synchrony is the causal factor triggering the illusion, further demonstrating the key role of material information conveyed by impact sounds in modulating the perceived material properties of the hand. This novel bodily illusion, the ‘Marble-Hand Illusion’, demonstrates that the perceived material of our body, surely the most stable attribute of our bodily self, can be quickly updated through multisensory integration.

If people can change physical perception of their hand in five minutes, our sense of the world around us must be as susceptible.

Our sense of our bodies in the world depends on the world around us. Our sense of our minds in the world depends on the people around us. We speak to ourselves with the same language we use with others.

If our core interpretations of self and other are wrong, we will make downstream mistakes and bring suffering to ourselves and others.

If those same interpretations are right, we will make downstream improvements.

The world answers us through science, reason, and imagination. Other people answer us on their own volition. We can get immediate truthful responses from them if they are willing.

Other people are the only entities in the world that can communicate in detail with us about their interpretations at a level commensurate with our own minds.

Since our interpretations include them, we can best improve those interpretations with the help of them.